under lock and key
Meaning: If something is under lock and key, it is kept in a very secure place.
elbow grease
Meaning: If something needs elbow grease, it needs a lot of hard physical work.
the jewel in the crown
Meaning: If something is the jewel in the crown, it's part of a group or set of similar things, and it's the best of them all.
caught red-handed
Meaning: If someone is caught red-handed, they are caught in the act of doing something wrong such as cheating or stealing.
jump down your throat | jump all over you
Meaning: If someone jumps down your throat, or jumps all over you, they strongly criticise you or scold you.
the year dot | the year one
Meaning: You can say "the year dot", or "the year one", when you're talking about a very, very long time ago.
a fair-weather friend
Meaning: A fair-weather friend is a person who will only be your friend when things are going well for you.
answer the call of nature
Meaning: If you answer the call of nature, you go to the toilet.
easy on the eye
Meaning: If something is easy on the eye, it is pleasant to look at.
under the table
Meaning: If something is done under the table, it's done secretly, usually because it's illegal or unethical.
kick the bucket
Meaning: If someone kicks the bucket, they die.
dirt cheap
Meaning: You can say something is dirt cheap if it costs very little money.
give the green light
Meaning: If you give something the green light, you give permission for it to be done, or allow it to happen.
par for the course
Meaning: If something is par for the course, it's what you'd expect it to be.
up a gum tree
Meaning: If you're up a gum tree, you're in trouble or have a serious problem.